I recently went on to the rogue trader store to browse some of the customisable options I could buy for my characters and I noticed that it didn't say whether the armour you could buy was a full set or just the armour piece shown, it also didn't say in the description or anything about it being just a chest piece or anything so...

TL;DR
If I was to buy say the Relic armour would it be the armour set or just the armour piece shown.

(Posted in suggestion sub-forum because a Rogue Trader one doesn't exist. also it might be a good idea in the descriptions for such purchasables to state what you'd get in plain English to prevent any accidents.

I think it is just the piece shown because the space marine one has a chest plat ans shoulder so I dont thinkthey would effect an entire set.

Yeah they should clearly state this asap in the description, though i sadly think it will be breastplate/shoulderpad only.

Which is ridiculous considering they are charging 15$ for the Ossified Breastplate, not anything else.
It looks (arguably) nice, but not 15$ nice.

i'm wrong or space marine are the only one that can use both of the rogue item at this point?

Im not understanding the question.

space marine have shoulder +armor.
other faction have 2 armor

Ah, yeah we do seem to be lacking in shoulderpads for other races.
But theres still 18 months of content to go, im sure the devs will deliver.
The pricings are still wack though.